Attachment devices and associated methods of use with a nerve stimulation charging device

ABSTRACT

Devices, systems and methods for transcutaneous charging of implanted medical devices are provided herein. Such devices include a portable charging device and an attachment device for affixing the portable charging device to a skin of the patient in a suitable location and alignment over the implanted medical device to facilitate charging. The attachment device can include a frame having an opening through which the charging device is mounted and one or more tabs extending laterally from the opening, each tab including an adhesive surface and being movable from a first position extending away from a skin of the patient to facilitate positioning of the charging device and a second position extending toward the skin of the patient so as to engage the skin of the patient and affix the charging device to the patient after being properly positioned.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims the benefit of priority of U.S. ProvisionalApplication No. 62/101,884, filed on Jan. 9, 2015, the entire contentsof which are incorporated herein by reference.

The present application is related to U.S. Provisional PatentApplication Nos. 62/038,122 filed on Aug. 15, 2014, entitled “Devicesand Methods for Anchoring of Neurostimulation Leads”; 62/038,131 filedon Aug. 15, 2014, entitled “External Pulse Generator Device andAssociated Methods for Trial Nerve Stimulation”; 62/041,611 filed onAug. 25, 2014, entitled “Electromyographic Lead Positioning andStimulation Titration in a Nerve Stimulation System for Treatment ofOveractive Bladder, Pain and Other Indicators”; and concurrently filedU.S. Provisional Patent Application Nos. 62/101,888, entitled“Electromyographic Lead Positioning and Stimulation Titration in a NerveStimulation System for Treatment of Overactive Bladder”; 62/101,888,entitled “Integrated Electromyographic Clinician Programmer For Use Withan Implantable Neurostimulator”; 62/101,897, entitled “Systems andMethods for Neurostimulation Electrode Configurations Based on NeuralLocalization”; 62/101,666, entitled “Patient Remote and AssociatedMethods of Use With a Nerve Stimulation System”; and 62/101,782,entitled “Improved Antenna and Methods of Use For an Implantable NerveStimulator,” all filed on Jan. 9, 2015, each of which is assigned to thesame assignee as the present application, and incorporated herein byreference in its entirety for all purposes.

FIELD OF THE INVENTION

The present invention relates to neurostimulation treatment systems andassociated devices, as well as methods of treatment, implantation andconfiguration of such treatment systems.

BACKGROUND OF THE INVENTION

Treatments with implantable neurostimulation systems have becomeincreasingly common in recent years. While such systems have shownpromise in treating a number of conditions, effectiveness of treatmentmay vary considerably between patients. A number of factors may lead tothe very different outcomes that patients experience, and viability oftreatment can be difficult to determine before implantation. Forexample, stimulation systems often make use of an array of electrodes totreat one or more target nerve structures. The electrodes are oftenmounted together on a multi-electrode lead, and the lead implanted intissue of the patient at a position that is intended to result inelectrical coupling of the electrode to the target nerve structure,typically with at least a portion of the coupling being provided viaintermediate tissues. Other approaches may also be employed, forexample, with one or more electrodes attached to the skin overlying thetarget nerve structures, implanted in cuffs around a target nerve, orthe like. Regardless, the physician will typically seek to establish anappropriate treatment protocol by varying the electrical stimulationthat is applied to the electrodes.

Current stimulation electrode placement/implantation techniques andknown treatment setting techniques suffer from significantdisadvantages. The nerve tissue structures of different patients can bequite different, with the locations and branching of nerves that performspecific functions and/or enervate specific organs being challenging toaccurately predict or identify. The electrical properties of the tissuestructures surrounding a target nerve structure may also be quitedifferent among different patients, and the neural response tostimulation may be markedly dissimilar, with an electrical stimulationpulse pattern, pulse width, frequency, and/or amplitude that iseffective to reduce affect a body function one patient potentiallyimposing significant discomfort or pain on, or have limited effect for,another patient. Even in patients where implantation of aneurostimulation system provides effective treatment, frequentadjustments and changes to the stimulation protocol are often requiredbefore a suitable treatment program can be determined, often involvingrepeated office visits and significant discomfort for the patient beforeefficacy is achieved. While a number of complex and sophisticated leadstructures and stimulation setting protocols have been implemented toseek to overcome these challenges, the variability in lead placementresults, the clinician time to establish suitable stimulation signals,and the discomfort (and in cases the significant pain) that is imposedon the patient remain less than ideal. In addition, the lifetime andbattery life of such devices is relatively short, such that implantedsystems are routinely replaced every few years, which requiresadditional surgeries, patient discomfort, and significant costs tohealthcare systems.

While rechargeable implanted devices have been investigated, thelocation and depth at which neurostimulation devices are implanted makesrecharging of such devices difficult. For example, neurostimulationdevices are typically implanted beneath a thin layer of muscle and fattytissues in a lower back region such that conventional methods mayutilize invasive techniques, such as recharging through a transcutaneouscable, or increased device size which may cause discomfort and limitedmobility for the patient. Furthermore, given the location at which suchdevices are implanted—the lower back—attaching a recharging cable ordevice can be difficult, if not impossible, for a patient to performwithout the aid of another person.

In view of these drawbacks associated with conventional systems, thetremendous benefits of these neural stimulation therapies have not yetbeen fully realized. Therefore, it would be desirable to provideimproved methods, systems and devices for facilitating recharging of animplanted neurostimulation device. It would be particularly helpful toprovide such systems and methods that recharge an implantedneurostimulation device in a non-invasive manner, while improving easeof use for the patient as well improved patient comfort and mobilityduring charging.

BRIEF SUMMARY OF THE INVENTION

Systems, devices and methods of the invention presented herein pertainto transcutaneous charging of an implanted medical device. Inparticular, the invention pertains to device and methods that facilitatepositioning and alignment of a charging device and affixation of thecharging device in the proper position and/or alignment to the patient.

In one aspect, a rechargeable medical implant system in accordance withembodiments of the invention includes: an implantable medical devicehaving a rechargeable power source for powering the device whileimplanted within a patient and a wireless power receiving unit coupledwith the rechargeable power source; a portable charging device having awireless power transmitting unit configured to magnetically couple withthe wireless power receiving unit of the implantable device so as torecharge the rechargeable power source; and a carrier removablycoupleable with the charging device, the carrier having an adhesivesurface for adhering to a skin surface of the patient, wherein theadhesive surface includes a biocompatible adhesive with sufficientadhesive strength to adhere to the patient's skin surface and supportthe carrier coupled with the charging device for at least a duration oftime sufficient to recharge the implanted medical device. The wirelesspower transmitting unit of the charging device includes a charging coilconfigured for magnetically coupling with the wireless receiving unitwhen the charging device at least partially engages the patient's skinsurface and is positioned at least partially over the implantablemedical device, wherein the carrier secures the charging devicesubstantially flat against the patient's skin.

In some embodiments, a carrier device in accordance with aspects of theinvention includes one or more movable tabs on which an adhesive surfaceis disposed, each of the one or more tabs being movable between a firstposition and a second position when the carrier is coupled with thecharging device placed against the patient's skin. In the firstposition, the one or more tabs are spaced away from the patient's skinto facilitate manual positioning of the charging device along thepatient's skin. In the second position, the one or more tabs are urgedagainst the patient's skin to facilitate secure attachment of thecarrier to the patient's skin with the adhesive surface for the durationof charging.

In some embodiments, the carrier device includes one or more tabs extendcircumferentially, at least partly, about the charging device when thecarrier is coupled with the charging device so as to secure the chargingdevice substantially flat against the patient's skin when the carrier isadhered to the skin of the patient. The carrier may include a frame towhich one or more tabs are attached, wherein the frame defines amounting interface at which the charging device is removably coupled.The mounting interface of the carrier is configured to allow manualrotation of the charging device relative to the carrier while releasablycoupled with the carrier.

In one aspect, the carrier includes a mounting interface configured witha dimensional fit that allows rotation of the charging device when thecharging device is subjected to a moment force and sufficient frictionto maintain angular fixation of the charging device within the carrierwhen the charging device is static. In some embodiments, the chargingdevice is defined by a circular or puck-shaped housing supporting and/orencasing the wireless power transmitting unit and associated chargingcoil at least partially within a protruding circular portion of thehousing. The frame of the carrier comprises a circular ring and themounting interface comprises a ridge along an inside edge of thecircular ring that interfaces with an outer edge of the protrudingportion of the charging device. The mounting can be configured toresiliently receive the protruding circular portion of the chargingdevice within a snap-fit.

In some embodiments, the carrier device includes three or more tabsdisposed circumferentially about a central frame of the device andextending laterally outward from the frame, each tab being deflectablebetween first and second positions. In one aspect, the tabs are formedof a material that is sufficiently stiff and flexible to resilientlyinvert (pass over center) between the first and second positions. Theframe and the one or more tabs can be integrally formed of a polymericmaterial and may be disposable.

In one aspect, the carrier device includes a coupling interface thatreleasably couples to the charger device and has one or more movabletabs having adhesive portions for securely adhering to a skin of thepatient, the adhesive portions being isolated from the charger device.In some embodiments, the adhesive portions are disposed on the one ormore tabs so that the adhesive portions are not in contact with asurface of the charging device. Such a configuration is advantageous asit avoids accumulation of residual adhesive on the charger device, whichis re-used over many charging sessions.

In another aspect, the charger device can be disposable, the adhesiveportions providing secure attachment to the patient for at least asufficient duration of time to charge the device. The carrier device canthen be readily removed from the charger device and discarded orrecycled after the charging session is complete. In some embodiments,the carrier device is provided to a patient with one or more linersdisposed over the adhesive portions to preserve and protect the adhesiveuntil ready for use. A single liner that extends over all adhesiveportions can be used so that the charger device can be secured and thesingle liner removed thereby exposing all adhesive portions. In someembodiments, the patient is provided with multiple disposable carrierdevices, such as a pack of carrier devices.

In another aspect, a carrier device for a portable charging deviceconfigured for transcutaneous charging of an neurostimulator deviceimplanted in a patient is provided herein. Such carrier devices candefined by a semi-rigid or rigid frame configured for removably couplingwith the charging device, wherein the frame includes an opening throughwhich a portion of the charging device extends when the charging deviceis coupled with the frame; and one or more tabs attached to the frameand extending laterally outward from the opening of the frame, whereinthe one or more tabs include an adhesive surface having a biocompatibleadhesive with sufficient adhesive strength to adhere to a skin surfaceof the patient and support the carrier coupled with the charging devicefor a duration of time sufficient to recharge the implantedneurostimulator. Each of the one or more tabs is movable between a firstposition and a second position when the carrier is coupled with thecharging device placed against the patient's skin, wherein in the firstposition, the one or more tabs are spaced away from the patient's skinto facilitate manual positioning of the charging device along thepatient's skin and, in the second position, the one or more tabs areurged against the patient's skin to facilitate secure attachment of thecarrier to the patient's skin with the adhesive surface for the durationof charging. Such carrier devices may include any of the featuresdescribed in the systems above.

In some embodiments, the charging device carrier includes a framedefined by a circular ring having a circular opening dimensioned tofittingly received a circular protruding portion of the charging devicehaving a charging coil therein. The carrier includes one or more tabsdisposed circumferentially about the opening that extend laterallyoutward as to support and maintain the charging device substantiallyflat against the patient's skin when the charging device is coupled tothe carrier and the tabs are adhered to the skin of the patient.

Methods of transcutaneously charging an implanted medical device in apatient in accordance with aspects of the invention are also providedherein. Such methods includes steps of: removably coupling a portablecharging device having a housing and a charging coil disposed thereinwith a carrier having one or more tabs with a biocompatible adhesivesurface, the one or more tabs being moveable between a first positionand a second position; non-invasively engaging a bottom surface of thecharging device at least partially against a skin surface of the patientwhile mounted within the carrier with the one or more tabs in the firstposition spaced a distance away from the skin surface of the patient;positioning the charging device until it is at least partiallypositioned over or proximate the implanted medical device; and movingthe one or more tabs from the first position to the second position sothat the adhesive surface contacts and adheres to the skin of thepatient sufficiently to support the charging device coupled with thecarrier for a duration of time sufficient to charge the implanteddevice.

In some embodiments, positioning the charging device includes moving thecharging device along the skin surface of the patient near the implanteddevice until the charging device outputs user feedback that indicates tothe patient that the charging device is properly positioned. Typically,the first alert can be audible and/or haptic user feedback. The methodmay further include rotating the charging device relative to the carrierwhile the one or more tabs secure the carrier to the skin surface of thepatient until the charging device is rotationally aligned with theimplanted device, which may be indicated by user feedback, such as asecond alert. In one aspect, each of engaging the bottom surface of thecharging device with the skin of the patient, positioning the chargingdevice, rotating the charging device relative the carrier, and movingthe one or more tabs to the second position is performed with a singlehand of the patient, thereby providing improved patient comfort and easeof use.

In some embodiments, the charge device carrier includes a belt. The beltcan be formed of a breathable stretchable material and include acorresponding coupling feature on each opposing end adapted toreleasably couple with each other to allow a patient to adjust the beltto a mid-section as desired. A circular aperture can be disposed in anintermediate portion of the belt. The circular aperture is dimensionedto fittingly receive a protruding circular portion of the portablecharging device. A semi-rigid or rigid frame circumscribes the circularaperture and has a mounting interface adapted for removably couplingwith the charging device so that the protruding circular portion of thecharging device protrudes through the circular aperture and engages skinof the patient when the charging device is coupled to the belt worn onthe mid-section of the patient. In some embodiments, the mountinginterface is axisymmetric about a normal axis extending through a centerof the circular aperture so as to allow the patient to manually rotatethe charging device when coupled with the belt to a particularrotational alignment.

In some embodiments, methods of transcutaneously charging an implantedmedical device in a patient include removably coupling a portablecharging device having a housing and a charging coil within a carrierbelt having a circular aperture so that the circular bottom portionprotrudes through the aperture when coupled. A bottom surface of thecharging device is non-invasively engaged with at least partiallyagainst a skin surface of the patient while mounted within the carrierbelt. The charging device is positioned by the patient until at leastpartially positioned over or proximate the implanted medical device asindicated by a first audible and/or haptic signal from the chargingdevice. The belt is adjusted by releasably coupling correspondingcoupling features on opposite ends of the belt. The belt can bepositioned before, during or after positioning of the charging device bythe patient. The method can further include manually rotating thecharging device while coupled within the belt until a second audibleand/or haptic signal indicates an acceptable charging alignment forcharging.

In one aspect, a method of transcutaneously charging an implantedmedical device in a patient includes use of different indicators (e.g.audible and/or haptic alerts) to assist a patient in charging of theimplanted medical device with a portable charging device. Such methodscan include: placing a portable charger device on the patient tofacilitate charging of an implanted neurostimulation within the patient;positioning the portable charger device until the charging deviceoutputs a first indicator to the patient indicating that the chargingdevice is proximate or suitably positioned over the implanted device forcharging; adjusting a position of the portable charger device or anattachment device supporting the charger device in response to a secondindicator output by the charging device indicating an interruption incharging; and removing the charging device after a third indication isoutput by the charging device indicating completion of charging.Typically, each of the first, second and third indicators is unique soas to be readily identifiable by the patient. Each of the first, secondand third indicators can be an audible alert and/or a haptic alert. Insome embodiments, the first alert is a sustained tone. The secondindicator can be a periodic vibration and/or a series of short tones,such as three beeps and vibration repeated every few seconds. The thirdindicator can include a repeating series of short tones that isdifferent from that of the second indicator, for example, a series ofrising tones that repeats, to alert the patient that charging iscomplete so that the charging device can be removed.

In another aspect, a system in accordance with the invention can includean implantable medical device and a portable charging device having anindicator graphic for visually representing a target alignment of thecharging device relative the implanted medical device. Such a system caninclude an implantable medical device having a rechargeable power sourcefor powering the device while implanted within a patient and a wirelesspower receiving unit coupled with the rechargeable power source; and aportable charging device having a wireless power transmitting unitconfigured to magnetically couple with the wireless power receiving unitof the implantable device for recharging of the rechargeable powersource. The portable charging device can include a planar surface forengaging a skin of the patient over the implanted medical device tofacilitate charging. The indicator graphic can be provided on the planarsurface and/or on the opposing outward facing surface and represent atarget alignment of the charging device relative the implanted medicaldevice to facilitate alignment of the charging device by the patient.The indicator can be a graphic that is the size and shape (e.g. outline)of the implanted medical device, which can serve as a visual prompt orreminder to the patient as to the desired alignment of the chargingdevice relative the implanted medical device. The system can furtherinclude a carrier device for supporting the charging device in thedesired alignment, such as in any of the embodiments described herein.

Further areas of applicability of the present disclosure will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples, whileindicating various embodiments, are intended for purposes ofillustration only and are not intended to necessarily limit the scope ofthe disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates a nerve stimulation system, whichincludes a clinician programmer and a patient remote used in positioningand/or programming of both a trial neurostimulation system and apermanently implanted neurostimulation system, in accordance withaspects of the invention.

FIGS. 2A-2C show diagrams of the nerve structures along the spine, thelower back and sacrum region, which may be stimulated in accordance withaspects of the invention.

FIG. 3A shows an example of a fully implanted neurostimulation system inaccordance with aspects of the invention.

FIG. 3B shows an example of a neurostimulation system having a partlyimplanted stimulation lead and an external pulse generator adhered tothe skin of the patient for use in a trial stimulation, in accordancewith aspects of the invention.

FIG. 4 shows an example of a neurostimulation system having animplantable stimulation lead, an implantable pulse generator, and anexternal charging device, in accordance with aspects of the invention.

FIGS. 5A-5C show detail views of an implantable pulse generator andassociated components for use in a neurostimulation system, inaccordance with aspects of the invention.

FIG. 6A shows a charging device configured for transcutaneous, wirelesscharging of an implanted neurostimulation device, in accordance withaspects of the invention.

FIG. 6B shows accessories for charging a portable charging device, inaccordance with aspects of the invention

FIGS. 6C-6D shows another portable charging device and an associateddocking station for charging the device, respectively, in accordancewith aspects of the invention.

FIG. 7A shows an affixation device comprising an adhesive carrieradapted for use with a portable charging device, in accordance withaspects of the invention.

FIG. 7B shows another affixation device comprising a belt, in accordancewith aspects of the invention.

FIG. 7C shows another affixation device comprising a belt, in accordancewith aspects of the invention.

FIGS. 8A-8B show manual coupling of an adhesive carrier device havingadhesive tabs to the portable charging device in FIG. 6C, in accordancewith aspects of the invention.

FIGS. 8C-8D show cross-sections of an adhesive carrier device havingadhesive tabs in a first position and a second position, in accordancewith aspects of the invention.

FIGS. 9A-9F illustrate a method of transcutaneously charging animplanted medical device using a carrier device, in accordance withaspects of the invention.

FIG. 10 illustrate examples of charging device placement over animplanted IPG, in accordance with aspects of the invention.

FIGS. 11A-11C illustrate a method of transcutaneously charging animplanted medical device using a carrier device, in accordance withaspects of the invention.

FIG. 12 illustrate a method of transcutaneously charging an implantedmedical device by rotating the device to provide optimal alignment, inaccordance with aspects of the invention.

FIG. 13 schematically illustrate a method of transcutaneously chargingan implanted medical device using a carrier device, in accordance withaspects of the invention.

FIGS. 14A-14C schematically illustrate methods of transcutaneouslycharging an implanted medical device facilitated by use of variousindicators or alerts from the charging device, in accordance withaspects of the invention.

FIG. 15 schematically illustrates a method of transcutaneously chargingan implanted medical device using a charging device that outputsdiffering indicators to the patient, in accordance with aspects of theinvention.

FIG. 16 illustrates a charging device having a graphical indicator thatrepresents a target alignment of the charging device relative theimplanted medical device, in accordance with aspects of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to neurostimulation treatment systems andassociated devices, as well as methods of treatment,implantation/placement and configuration of such treatment systems. Inparticular embodiments, the invention relates to sacral nervestimulation treatment systems configured to treat bladder dysfunctions,including overactive bladder (“OAB”), as well as fecal dysfunctions andrelieve symptoms associated therewith. In addition, the descriptionsherein may also be used to treat other forms of urinary dysfunction andto treat fecal dysfunction, therefore, throughout the description itshould be understood that what is described for OAB applies equally toother forms of urinary dysfunction and fecal dysfunction. It will beappreciated however that the present invention may also be utilized forany variety of neuromodulation uses, such as fecal dysfunction, thetreatment of pain or other indications, such as movement or affectivedisorders, as will be appreciated by one of skill in the art.

I. Neurostimulation Indications

Neurostimulation (or neuromodulation as may be used interchangeablyhereunder) treatment systems, such as any of those described herein, canbe used to treat a variety of ailments and associated symptoms, such asacute pain disorders, movement disorders, affective disorders, as wellas bladder and bowel related dysfunction. Examples of pain disordersthat may be treated by neurostimulation include failed back surgerysyndrome, reflex sympathetic dystrophy or complex regional painsyndrome, causalgia, arachnoiditis, and peripheral neuropathy. Movementorders include muscle paralysis, tremor, dystonia and Parkinson'sdisease. Affective disorders include depressions, obsessive-compulsivedisorder, cluster headache, Tourette syndrome and certain types ofchronic pain. Bladder related dysfunctions include but are not limitedto OAB, urge incontinence, urgency-frequency, and urinary retention. OABcan include urge incontinence and urgency-frequency alone or incombination. Urge incontinence is the involuntary loss or urineassociated with a sudden, strong desire to void (urgency).Urgency-frequency is the frequent, often uncontrollable urges to urinate(urgency) that often result in voiding in very small amounts(frequency). Urinary retention is the inability to empty the bladder.Neurostimulation treatments can be configured to address a particularcondition by effecting neurostimulation of targeted nerve tissuesrelating to the sensory and/or motor control associated with thatcondition or associated symptom.

In one aspect, the methods and systems described herein are particularlysuited for treatment of urinary and fecal dysfunctions. These conditionshave been historically under-recognized and significantly underserved bythe medical community. OAB is one of the most common urinarydysfunctions. It is a complex condition characterized by the presence ofbothersome urinary symptoms, including urgency, frequency, nocturia andurge incontinence. It is estimated that about 40 million Americanssuffer from OAB. Of the adult population, about 16% of all men and womenlive with OAB symptoms.

OAB symptoms can have a significant negative impact on the psychosocialfunctioning and the quality of life of patients. People with OAB oftenrestrict activities and/or develop coping strategies. Furthermore, OABimposes a significant financial burden on individuals, their families,and healthcare organizations. The prevalence of co-morbid conditions isalso significantly higher for patients with OAB than in the generalpopulation. Co-morbidities may include falls and fractures, urinarytract infections, skin infections, vulvovaginitis, cardiovascular, andcentral nervous system pathologies. Chronic constipation, fecalincontinence, and overlapping chronic constipation occur more frequentlyin patients with OAB.

Conventional treatments of OAB generally include lifestyle modificationsas a first course of action. Lifestyle modifications include eliminatingbladder irritants (such as caffeine) from the diet, managing fluidintake, reducing weight, stopping smoking, and managing bowelregularity. Behavioral modifications include changing voiding habits(such as bladder training and delayed voiding), training pelvic floormuscles to improve strength and control of urethral sphincter,biofeedback and techniques for urge suppression. Medications areconsidered a second-line treatment for OAB. These includeanti-cholinergic medications (oral, transdermal patch, and gel) and oralbeta-3 adrenergic agonists. However, anti-cholinergics are frequentlyassociated with bothersome, systemic side effects including dry mouth,constipation, urinary retention, blurred vision, somnolence, andconfusion. Studies have found that more than 50% of patients stop usinganti-cholinergic medications within 90 days due to a lack of benefit,adverse events, or cost.

When these approaches are unsuccessful, third-line treatment optionssuggested by the American Urological Association include intradetrusor(bladder smooth muscle) injections of botulinum toxin (BTX),Percutaneous Tibial Nerve Stimulation (PTNS) and Sacral NerveStimulation (SNM). BTX is administered via a series of intradetrusorinjections under cystoscopic guidance, but repeat injections of BTX aregenerally required every 4 to 12 months to maintain effect and BTX mayundesirably result in urinary retention. A number or randomizedcontrolled studies have shown some efficacy of BTX injections in OABpatients, but long-term safety and effectiveness of BTX for OAB islargely unknown.

PTNS therapy consists of weekly, 30-minute sessions over a period of 12weeks, each session using electrical stimulation that is delivered froma hand-held stimulator to the sacral plexus via the tibial nerve. Forpatients who respond well and continue treatment, ongoing sessions,typically every 3-4 weeks, are needed to maintain symptom reduction.There is potential for declining efficacy if patients fail to adhere tothe treatment schedule. Efficacy of PTNS has been demonstrated in a fewrandomized-controlled studies, however, there is limited data on PTNSeffectiveness beyond 3-years and PTNS is not recommended for patientsseeking a cure for urge urinary incontinence (UUI) (e.g., 100% reductionin incontinence episodes) (EAU Guidelines).

II. Sacral Neuromodulation

SNM is an established therapy that provides a safe, effective,reversible, and long-lasting treatment option for the management of urgeincontinence, urgency-frequency, and non-obstructive urinary retention.SNM therapy involves the use of mild electrical pulses to stimulate thesacral nerves located in the lower back. Electrodes are placed next to asacral nerve, usually at the S3 level, by inserting the electrode leadsinto the corresponding foramen of the sacrum. The electrodes areinserted subcutaneously and are subsequently attached to an implantablepulse generator (IPG). The safety and effectiveness of SNM for thetreatment of OAB, including durability at five years for both urgeincontinence and urgency-frequency patients, is supported by multiplestudies and is well-documented. SNM has also been approved to treatchronic fecal incontinence in patients who have failed or are notcandidates for more conservative treatments.

A. Implantation of Sacral Neuromodulation System

Currently, SNM qualification has a trial phase, and is followed ifsuccessful by a permanent implant. The trial phase is a test stimulationperiod where the patient is allowed to evaluate whether the therapy iseffective. Typically, there are two techniques that are utilized toperform the test stimulation. The first is an office-based proceduretermed the Percutaneous Nerve Evaluation (PNE) and the other is a stagedtrial.

In the PNE, a foramen needle is typically used first to identify theoptimal stimulation location, usually at the S3 level, and to evaluatethe integrity of the sacral nerves. Motor and sensory responses are usedto verify correct needle placement, as described in Table 1 below. Atemporary stimulation lead (a unipolar electrode) is then placed nearthe sacral nerve under local anesthesia. This procedure can be performedin an office setting without fluoroscopy. The temporary lead is thenconnected to an external pulse generator (EPG) taped onto the skin ofthe patient during the trial phase. The stimulation level can beadjusted to provide an optimal comfort level for the particular patient.The patient will monitor his or her voiding for 3 to 7 days to see ifthere is any symptom improvement. The advantage of the PNE is that it isan incision free procedure that can be performed in the physician'soffice using local anesthesia. The disadvantage is that the temporarylead is not securely anchored in place and has the propensity to migrateaway from the nerve with physical activity and thereby cause failure ofthe therapy. If a patient fails this trial test, the physician may stillrecommend the staged trial as described below. If the PNE trial ispositive, the temporary trial lead is removed and a permanentquadri-polar tined lead is implanted along with an IPG under generalanesthesia. Other neuromodulation applications may have any number ofelectrodes and more than one lead as the therapy may require.

A staged trial involves the implantation of the permanent quadri-polartined stimulation lead into the patient from the start. It also requiresthe use of a foramen needle to identify the nerve and optimalstimulation location. The lead is implanted near the S3 sacral nerve andis connected to an EPG via a lead extension. This procedure is performedunder fluoroscopic guidance in an operating room and under local orgeneral anesthesia. The EPG is adjusted to provide an optimal comfortlevel for the patient and the patient monitors his or her voiding for upto two weeks. If the patient obtains meaningful symptom improvement, heor she is considered a suitable candidate for permanent implantation ofthe IPG under general anesthesia, typically in the upper buttock area,as shown in FIGS. 1 and 3A.

TABLE 1 Motor and Sensory Responses of SNM at Different Sacral NerveRoots Response Nerve Innervation Pelvic Floor Foot/calf/leg SensationS2 - Primary somatic “Clamp” * of anal Leg/hip rotation, Contraction ofbase contributor of pudendal sphincter plantar flexion of entire ofpenis, vagina nerve for external foot, contraction of calf sphincter,leg, foot S3 - Virtually all pelvic “bellows” ** of Plantar flexion ofgreat Pulling in rectum, autonomic functions and perineum toe,occasionally other extending forward striated mucle (levetor ani) toesto scrotum or labia S4 - Pelvic autonomic “bellows” ** No lowerextremity Pulling in rectum and somatic; No leg pr motor stimulationonly foot * Clamp: contraction of anal sphincter and, in males,retraction of base of penis. Move buttocks aside and look foranterior/posterior shortening of the perineal structures. ** Bellows:lifting and dropping of pelvic floor. Look for deepening and flatteningof buttock groove

In regard to measuring outcomes for SNM treatment of voidingdysfunction, the voiding dysfunction indications (e.g., urgeincontinence, urgency-frequency, and non-obstructive urinary retention)are evaluated by unique primary voiding diary variables. The therapyoutcomes are measured using these same variables. SNM therapy isconsidered successful if a minimum of 50% improvement occurs in any ofprimary voiding diary variables compared with the baseline. For urgeincontinence patients, these voiding diary variables may include: numberof leaking episodes per day, number of heavy leaking episodes per day,and number of pads used per day. For patients with urgency-frequency,primary voiding diary variables may include: number of voids per day,volume voided per void and degree of urgency experienced before eachvoid. For patients with retention, primary voiding diary variables mayinclude: catheterized volume per catheterization and number ofcatheterizations per day. For FI patients, the outcome measures capturedby the voiding diary include: number of leaking episodes per week,number of leaking days per week, and degree of urgency experiencedbefore each leak.

The mechanism of action of SNM is multifactorial and impacts theneuro-axis at several different levels. In patients with OAB, it isbelieved that pelvic and/or pudendal afferents can activate theinhibitory reflexes that promote bladder storage by inhibiting theafferent limb of an abnormal voiding reflex. This blocks input to thepontine micturition center, thereby restricting involuntary detrusorcontractions without interfering with normal voiding patterns. Forpatients with urinary retention, SNM is believed to activate the pelvicand/or pudendal nerve afferents originating from the pelvic organs intothe spinal cord. At the level of the spinal cord, these afferents mayturn on voiding reflexes by suppressing exaggerated guarding reflexes,thus relieving symptoms of patients with urinary retention so normalvoiding can be facilitated. In patients with fecal incontinence, it ishypothesized that SNM stimulates pelvic and/or pudendal afferent somaticfibers that inhibit colonic propulsive activity and activates theinternal anal sphincter, which in turn improves the symptoms of fecalincontinence patients. The present invention relates to a system adaptedto deliver neurostimulation to targeted nerve tissues in a manner thatthat results in partial or complete activation of the target nervefibers, causes the augmentation or inhibition of neural activity innerves, potentially the same or different than the stimulation target,that control the organs and structures associated with bladder and bowelfunction.

B. Positioning Neurostimulation Leads with EMG

While conventional sacral nerve stimulation approaches have shownefficacy in treatment of bladder and bowel related dysfunction, thereexists a need to improve positioning of the neurostimulation leads andconsistency between the trial and permanent implantation positions ofthe lead. Neurostimulation relies on consistently delivering therapeuticstimulation from a pulse generator, via one or more neurostimulationelectrodes, to particular nerves or targeted regions. Theneurostimulation electrodes are provided on a distal end of animplantable lead that can be advanced through a tunnel formed in patienttissue. Implantable neurostimulation systems provide patients with greatfreedom and mobility, but it may be easier to adjust theneurostimulation electrodes of such systems before they are surgicallyimplanted. It is desirable for the physician to confirm that the patienthas desired motor and/or sensory responses before implanting an IPG. Forat least some treatments (including treatments of at least some forms ofurinary and/or fecal dysfunction), demonstrating appropriate motorresponses may be highly beneficial for accurate and objective leadplacement while the sensory response may not be required or notavailable (e.g., patient is under general anesthesia).

Placement and calibration of the neurostimulation electrodes andimplantable leads sufficiently close to specific nerves can bebeneficial for the efficacy of treatment. Accordingly, aspects andembodiments of the present disclosure are directed to aiding andrefining the accuracy and precision of neurostimulation electrodeplacement. Further, aspects and embodiments of the present disclosureare directed to aiding and refining protocols for setting therapeutictreatment signal parameters for a stimulation program implementedthrough implanted neurostimulation electrodes.

Prior to implantation of the permanent device, patients may undergo aninitial testing phase to estimate potential response to treatment. Asdiscussed above, PNE may be done under local anesthesia, using a testneedle to identify the appropriate sacral nerve(s) according to asubjective sensory response by the patient. Other testing procedures caninvolve a two-stage surgical procedure, where a quadri-polar tined leadis implanted for a testing phase (phase 1) to determine if patients showa sufficient reduction in symptom frequency, and if appropriate,proceeding to the permanent surgical implantation of a neuromodulationdevice. For testing phases and permanent implantation, determining thelocation of lead placement can be dependent on subjective qualitativeanalysis by either or both of a patient or a physician.

In exemplary embodiments, determination of whether or not an implantablelead and neurostimulation electrode is located in a desired or correctlocation can be accomplished through use of electromyography (“EMG”),also known as surface electromyography. EMG, is a technique that uses anEMG system or module to evaluate and record electrical activity producedby muscles, producing a record called an electromyogram. EMG detects theelectrical potential generated by muscle cells when those cells areelectrically or neurologically activated. The signals can be analyzed todetect activation level or recruitment order. EMG can be performedthrough the skin surface of a patient, intramuscularly or throughelectrodes disposed within a patient near target muscles, or using acombination of external and internal structures. When a muscle or nerveis stimulated by an electrode, EMG can be used to determine if therelated muscle is activated, (i.e. whether the muscle fully contracts,partially contracts, or does not contract) in response to the stimulus.Accordingly, the degree of activation of a muscle can indicate whetheran implantable lead or neurostimulation electrode is located in thedesired or correct location on a patient. Further, the degree ofactivation of a muscle can indicate whether a neurostimulation electrodeis providing a stimulus of sufficient strength, amplitude, frequency, orduration to affect a treatment regimen on a patient. Thus, use of EMGprovides an objective and quantitative means by which to standardizeplacement of implantable leads and neurostimulation electrodes, reducingthe subjective assessment of patient sensory responses.

In some approaches, positional titration procedures may optionally bebased in part on a paresthesia or pain-based subjective response from apatient. In contrast, EMG triggers a measureable and discrete muscularreaction. As the efficacy of treatment often relies on precise placementof the neurostimulation electrodes at target tissue locations and theconsistent, repeatable delivery of neurostimulation therapy, using anobjective EMG measurement can substantially improve the utility andsuccess of SNM treatment. The measureable muscular reaction can be apartial or a complete muscular contraction, including a response belowthe triggering of an observable motor response, such as those shown inTable 1, depending on the stimulation of the target muscle. In addition,by utilizing a trial system that allows the neurostimulation lead toremain implanted for use in the permanently implanted system, theefficacy and outcome of the permanently implanted system is moreconsistent with the results of the trial period, which moreover leads toimproved patient outcomes. Moreover, the capability of the EMG systemsdescribed herein to quantitatively sense partial contraction canfacilitate the use of positioning and/or programming stimulation levelsbelow those appropriate for reliable subjective assessment by thepatient. Hence, pain associated with electrode positioning and/orprogramming may optionally be reduced or eliminated by the use ofsub-subjective EMG stimulation signals, with the programming and/orpositioning of some embodiments relying substantially, largely,primarily, or even entirely on sub-subjective stimulation signals.

C. Example Neurostimulation Systems

FIG. 1 schematically illustrates an exemplary nerve stimulation system,which includes both a trial neurostimulation system 200 and apermanently implanted neurostimulation system 100, in accordance withaspects of the invention. The EPG 80 and IPG 10 are each compatible withand wirelessly communicate with a clinician programmer 60 and a patientremote 70, which are used in positioning and/or programming the trialneurostimulation system 200 and/or permanently implanted system 100after a successful trial. As discussed above, the clinician programmercan include specialized software, specialized hardware, and/or both, toaid in lead placement, programming, re-programming, stimulation control,and/or parameter setting. In addition, each of the IPG and the EPGallows the patient at least some control over stimulation (e.g.,initiating a pre-set program, increasing or decreasing stimulation),and/or to monitor battery status with the patient remote. This approachalso allows for an almost seamless transition between the trial systemand the permanent system.

In one aspect, the clinician programmer 60 is used by a physician toadjust the settings of the EPG and/or IPG while the lead is implantedwithin the patient. The clinician programmer can be a tablet computerused by the clinician to program the IPG, or to control the EPG duringthe trial period. The clinician programmer can also include capabilityto record stimulation-induced electromyograms to facilitate leadplacement and programming. The patient remote 70 can allow the patientto turn the stimulation on or off, or to vary stimulation from the IPGwhile implanted, or from the EPG during the trial phase.

In another aspect, the clinician programmer 60 has a control unit whichcan include a microprocessor and specialized computer-code instructionsfor implementing methods and systems for use by a physician in deployingthe treatment system and setting up treatment parameters. The clinicianprogrammer generally includes a user interface which can be a graphicaluser interface, an EMG module, electrical contacts such as an EMG inputthat can couple to an EMG output stimulation cable, an EMG stimulationsignal generator, and a stimulation power source. The stimulation cablecan further be configured to couple to any or all of an access device(e.g., a foramen needle), a treatment lead of the system, or the like.The EMG input may be configured to be coupled with one or more sensorypatch electrode(s) for attachment to the skin of the patient adjacent amuscle (e.g., a muscle enervated by a target nerve). Other connectors ofthe clinician programmer may be configured for coupling with anelectrical ground or ground patch, an electrical pulse generator (e.g.,an EPG or an IPG), or the like. As noted above, the clinician programmercan include a module with hardware and computer-code to execute EMGanalysis, where the module can be a component of the control unitmicroprocessor, a pre-processing unit coupled to or in-line with thestimulation and/or sensory cables, or the like.

In some aspects, the clinician programmer is configured to operate incombination with an EPG when placing leads in a patient body. Theclinician programmer can be electronically coupled to the EPG wirelesslyduring test simulation or through a specialized cable set, and. andallow the clinician programmer to configure, modify, or otherwiseprogram the electrodes on the leads connected to the EPG.

The electrical pulses generated by the EPG and IPG are delivered to oneor more targeted nerves via one or more neurostimulation electrodes ator near a distal end of each of one or more leads. The leads can have avariety of shapes, can be a variety of sizes, and can be made from avariety of materials, which size, shape, and materials can be tailoredto the specific treatment application. While in this embodiment, thelead is of a suitable size and length to extend from the IPG and throughone of the foramen of the sacrum to a targeted sacral nerve, in variousother applications, the leads may be, for example, implanted in aperipheral portion of the patient's body, such as in the arms or legs,and can be configured to deliver electrical pulses to the peripheralnerve such as may be used to relieve chronic pain. It is appreciatedthat the leads and/or the stimulation programs may vary according to thenerves being targeted.

FIGS. 2A-2C show diagrams of various nerve structures of a patient,which may be used in neurostimulation treatments, in accordance withaspects of the invention. FIG. 2A shows the different sections of thespinal cord and the corresponding nerves within each section. The spinalcord is a long, thin bundle of nerves and support cells that extend fromthe brainstem along the cervical cord, through the thoracic cord and tothe space between the first and second lumbar vertebra in the lumbarcord. Upon exiting the spinal cord, the nerve fibers split into multiplebranches that innervate various muscles and organs transmitting impulsesof sensation and control between the brain and the organs and muscles.Since certain nerves may include branches that innervate certain organs,such as the bladder, and branches that innervate certain muscles of theleg and foot, stimulation of the nerve at or near the nerve root nearthe spinal cord can stimulate the nerve branch that innervate thetargeted organ, which may also result in muscle responses associatedwith the stimulation of the other nerve branch. Thus, by monitoring forcertain muscle responses, such as those in Table 1, either visually,through the use of EMG as described herein or both, the physician candetermine whether the targeted nerve is being stimulated. Whilestimulation at a certain level may evoke robust muscle responses visibleto the naked eye, stimulation at a lower level may still provideactivation of the nerve associated with the targeted organ while evokingno corresponding muscle response or a response only visible with EMG. Insome embodiments, this low level stimulation also does not cause anyparesthesia. This is advantageous as it allows for treatment of thecondition by neurostimulation without otherwise causing patientdiscomfort, pain or undesired muscle responses.

FIG. 2B shows the nerves associated with the lower back section, in thelower lumbar cord region where the nerve bundles exit the spinal cordand travel through the sacral foramens of the sacrum. In someembodiments, the neurostimulation lead is advanced through the foramenuntil the neurostimulation electrodes are positioned at the anteriorsacral nerve root, while the anchoring portion of the lead proximal ofthe stimulation electrodes are generally disposed dorsal of the sacralforamen through which the lead passes, so as to anchor the lead inposition. FIG. 2C shows detail views of the nerves of the lumbosacraltrunk and the sacral plexus, in particular, the S1-S5 nerves of thelower sacrum. The S3 sacral nerve is of particular interest fortreatment of bladder related dysfunction, and in particular OAB.

FIG. 3A schematically illustrates an example of a fully implantedneurostimulation system 100 adapted for sacral nerve stimulation.Neurostimulation system 100 includes an IPG implanted in a lower backregion and connected to a neurostimulation lead extending through the S3foramen for stimulation of the S3 sacral nerve. The lead is anchored bya tined anchor portion 30 that maintains a position of a set ofneurostimulation electrodes 40 along the targeted nerve, which in thisexample, is the anterior sacral nerve root S3 which enervates thebladder so as to provide therapy for various bladder relateddysfunctions. While this embodiment is adapted for sacral nervestimulation, it is appreciated that similar systems can be used intreating patients with, for example, chronic, severe, refractoryneuropathic pain originating from peripheral nerves or various urinarydysfunctions or still further other indications. Implantableneurostimulation systems can be used to either stimulate a targetperipheral nerve or the posterior epidural space of the spine.

Properties of the electrical pulses can be controlled via a controllerof the implanted pulse generator. In some embodiments, these propertiescan include, for example, the frequency, amplitude, pattern, duration,or other aspects of the electrical pulses. These properties can include,for example, a voltage, a current, or the like. This control of theelectrical pulses can include the creation of one or more electricalpulse programs, plans, or patterns, and in some embodiments, this caninclude the selection of one or more pre-existing electrical pulseprograms, plans, or patterns. In the embodiment depicted in FIG. 3A, theimplantable neurostimulation system 100 includes a controller in the IPGhaving one or more pulse programs, plans, or patterns that may bepre-programmed or created as discussed above. In some embodiments, thesesame properties associated with the IPG may be used in an EPG of apartly implanted trial system used before implantation of the permanentneurostimulation system 100.

FIG. 3B shows a schematic illustration of a trial neurostimulationsystem 200 utilizing an EPG patch 81 adhered to the skin of a patient,particularly to the abdomen of a patient, the EPG 80 being encasedwithin the patch. In one aspect, the lead is hardwired to the EPG, whilein another the lead is removably coupled to the EPG through a port oraperture in the top surface of the flexible patch 81. Excess lead can besecured by an additional adherent patch. In one aspect, the EPG patch isdisposable such that the lead can be disconnected and used in apermanently implanted system without removing the distal end of the leadfrom the target location. Alternatively, the entire system can bedisposable and replaced with a permanent lead and IPG. When the lead ofthe trial system is implanted, an EMG obtained via the clinicianprogrammer using one or more sensor patches can be used to ensure thatthe leads are placed at a location proximate to the target nerve ormuscle, as discussed previously.

In some embodiments, the trial neurostimulation system utilizes an EPG80 within an EPG patch 81 that is adhered to the skin of a patient andis coupled to the implanted neurostimulation lead 20 through a leadextension 22, which is coupled with the lead 20 through a connector 21.This extension and connector structure allows the lead to be extended sothat the EPG patch can be placed on the abdomen and allows use of a leadhaving a length suitable for permanent implantation should the trialprove successful. This approach may utilize two percutaneous incisions,the connector provided in the first incision and the lead extensionsextending through the second percutaneous incision, there being a shorttunneling distance (e.g., about 10 cm) there between. This technique mayalso minimize movement of an implanted lead during conversion of thetrial system to a permanently implanted system.

In one aspect, the EPG unit is wirelessly controlled by a patient remoteand/or the clinician programmer in a similar or identical manner as theIPG of a permanently implanted system. The physician or patient mayalter treatment provided by the EPG through use of such portable remotesor programmers and the treatments delivered are recorded on a memory ofthe programmer for use in determining a treatment suitable for use in apermanently implanted system. The clinician programmer can be used inlead placement, programming and/or stimulation control in each of thetrial and permanent nerve stimulation systems. In addition, each nervestimulation system allows the patient to control stimulation or monitorbattery status with the patient remote. This configuration isadvantageous as it allows for an almost seamless transition between thetrial system and the permanent system. From the patient's viewpoint, thesystems will operate in the same manner and be controlled in the samemanner, such that the patient's subjective experience in using the trialsystem more closely matches what would be experienced in using thepermanently implanted system. Thus, this configuration reduces anyuncertainties the patient may have as to how the system will operate andbe controlled such that the patient will be more likely to convert atrial system to a permanent system.

As shown in the detailed view of FIG. 3B, the EPG 80 is encased within aflexible laminated patch 81, which include an aperture or port throughwhich the EPG 80 is connected to the lead extension 22. The patch mayfurther an “on/off” button 83 with a molded tactile detail to allow thepatient to turn the EPG on and/or off through the outside surface of theadherent patch 81. The underside of the patch 81 is covered with askin-compatible adhesive 82 for continuous adhesion to a patient for theduration of the trial period. For example, a breathable strip havingskin-compatible adhesive 82 would allow the EPG 80 to remain attached tothe patient continuously during the trial, which may last over a week,typically two weeks to four weeks, or even longer.

FIG. 4 illustrates an example neurostimulation system 100 that is fullyimplantable and adapted for sacral nerve stimulation treatment. Theimplantable system 100 includes an IPG 10 that is coupled to aneurostimulation lead 20 that includes a group of neurostimulationelectrodes 40 at a distal end of the lead. The lead includes a leadanchor portion 30 with a series of tines extending radially outward soas to anchor the lead and maintain a position of the neurostimulationlead 20 after implantation. The lead 20 may further include one or moreradiopaque markers 25 to assist in locating and positioning the leadusing visualization techniques such as fluoroscopy. In some embodiments,the IPG provides monopolar or bipolar electrical pulses that aredelivered to the targeted nerves through one or more neurostimulationelectrodes. In sacral nerve stimulation, the lead is typically implantedthrough the S3 foramen as described herein.

In one aspect, the IPG is rechargeable wirelessly through conductivecoupling by use of a charging device 50 (CD), which is a portable devicepowered by a rechargeable battery to allow patient mobility whilecharging. The CD is used for transcutaneous charging of the IPG throughRF induction. The CD can either be patched to the patient's skin with anaffixation device, such as an adhesive carrier 1 or a belt 9. The CD maybe charged by plugging the CD directly into an outlet or by placing theCD in a charging dock or station 55 that connects to an AC wall outletor other power source.

The system may further include a patient remote 70 and clinicianprogrammer 60, each configured to wirelessly communicate with theimplanted IPG, or with the EPG during a trial, as shown in the schematicof the nerve stimulation system in FIG. 6. The clinician programmer 60may be a tablet computer used by the clinician to program the IPG andthe EPG. The device also has the capability to recordstimulation-induced electromyograms (EMGs) to facilitate lead placement,programming, and/or re-programming. The patient remote may be abattery-operated, portable device that utilizes radio-frequency (RF)signals to communicate with the EPG and IPG and allows the patient toadjust the stimulation levels, check the status of the IPG batterylevel, and/or to turn the stimulation on or off.

FIG. 5A-5C show detail views of the IPG and its internal components. Insome embodiments, the pulse generator can generate one or morenon-ablative electrical pulses that are delivered to a nerve to controlpain or cause some other desired effect, for example to inhibit,prevent, or disrupt neural activity for the treatment of OAB or bladderrelated dysfunction. In some applications, the pulses having a pulseamplitude in a range between 0 mA to 1,000 mA, 0 mA to 100 mA, 0 mA to50 mA, 0 mA to 25 mA, and/or any other or intermediate range ofamplitudes may be used. One or more of the pulse generators can includea processor and/or memory adapted to provide instructions to and receiveinformation from the other components of the implantableneurostimulation system. The processor can include a microprocessor,such as a commercially available microprocessor from Intel® or AdvancedMicro Devices, Inc.®, or the like. An IPG may include an energy storagefeature, such as one or more capacitors, one or more batteries, andtypically includes a wireless charging unit.

One or more properties of the electrical pulses can be controlled via acontroller of the IPG or EPG. In some embodiments, these properties caninclude, for example, the frequency, strength, pattern, duration, orother aspects of the timing and magnitude of the electrical pulses.These properties can further include, for example, a voltage, a current,or the like. This control of the electrical pulses can include thecreation of one or more electrical pulse programs, plans, or patterns,and in some embodiments, this can include the selection of one or morepre-existing electrical pulse programs, plans, or patterns. In oneaspect, the IPG 10 includes a controller having one or more pulseprograms, plans, or patterns that may be created and/or pre-programmed.In some embodiments, the IPG can be programmed to vary stimulationparameters including pulse amplitude in a range from 0 mA to 10 mA,pulse width in a range from 50 μs to 500 μs, pulse frequency in a rangefrom 5 Hz to 250 Hz, stimulation modes (e.g., continuous or cycling),and electrode configuration (e.g., anode, cathode, or off), to achievethe optimal therapeutic outcome specific to the patient. In particular,this allows for an optimal setting to be determined for each patienteven though each parameter may vary from person to person.

As shown in FIGS. 5A-5B, the IPG may include a header portion 11 at oneend and a ceramic portion 14 at the opposite end. The header portion 11houses a feed through assembly 12 and connector stack 13, while theceramic case portion 14 houses an antenna assembly 16 to facilitatewireless communication with the clinician program, the patient remote,and/or a charging coil to facilitate wireless charging with the CD. Theremainder of the IPG is covered with a titanium case portion 17, whichencases the printed circuit board, memory and controller components thatfacilitate the electrical pulse programs described above. In the exampleshown in FIG. 5C, the header portion of the IPG includes a four-pinfeed-through assembly 12 that couples with the connector stack 13 inwhich the proximal end of the lead is coupled. The four pins correspondto the four electrodes of the neurostimulation lead. In someembodiments, a Balseal® connector block is electrically connected tofour platinum/iridium alloy feed-through pins which are brazed to analumina ceramic insulator plate along with a titanium alloy flange. Thisfeed-through assembly is laser seam welded to a titanium-ceramic brazedcase to form a complete hermetic housing for the electronics. The numberof header electrical contacts is a function of the number of electrodesand leads used for any particular system configuration.

In some embodiments, such as that shown in FIG. 5A, the ceramic andtitanium brazed case is utilized on one end of the IPG where the ferritecoil and PCB antenna assemblies are positioned. A reliable hermetic sealis provided via a ceramic-to-metal brazing technique. The zirconiaceramic may comprise a 3Y-TZP (3 mol percent Yttria-stabilizedtetragonal Zirconia Polycrystals) ceramic, which has a high flexuralstrength and impact resistance and has been commercially utilized in anumber of implantable medical technologies. It will be appreciated,however, that other ceramics or other suitable materials may be used forconstruction of the IPG.

In one aspect, utilization of ceramic material provides an efficient,radio-frequency-transparent window for wireless communication with theexternal patient remote and clinician's programmer as the communicationantenna is housed inside the hermetic ceramic case. This ceramic windowhas further facilitated miniaturization of the implant while maintainingan efficient, radio-frequency-transparent window for long term andreliable wireless communication between the IPG and externalcontrollers, such as the patient remote and clinician programmer. TheIPG's wireless communication is generally stable over the lifetime ofthe device, unlike prior art products where the communication antenna isplaced in the header outside the hermetic case. The communicationreliability of such prior art devices tends to degrade due to the changein dielectric constant of the header material in the human body overtime.

In another aspect, the ferrite core is part of the charging coilassembly 15, shown in FIG. 5B, which is positioned inside the ceramiccase 14. The ferrite core concentrates the magnetic field flux throughthe ceramic case as opposed to the metallic case portion 17. Thisconfiguration maximizes coupling efficiency, which reduces the requiredmagnetic field and in turn reduces device heating during charging. Inparticular, because the magnetic field flux is oriented in a directionperpendicular to the smallest metallic cross section area, heatingduring charging is minimized. This configuration also allows the IPG tobe effectively charged at depth of 3 cm with the CD, when positioned ona skin surface of the patient near the IPG and reduces re-charging time.

FIG. 6 shows a setup for a test stimulation and EMG sensing using aclinician programmer 60. As discussed above, the clinician programmer 60is a tablet computer with software that runs on a standard operatingsystem. The clinician programmer 60 includes a communication module, astimulation module and an EMG sensing module. The communication modulecommunicates with the IPG and/or EPG in the medical implantcommunication service frequency band for programming the IPG and/or EPG.

In order to confirm correct lead placement, it is desirable for thephysician to confirm that the patient has both adequate motor andsensory responses before transitioning the patient into the staged trialphase or implanting the permanent IPG. However, sensory response is asubjective evaluation and may not always be available, such as when thepatient is under general anesthesia. Experiments have shown thatdemonstrating appropriate motor responses is advantageous for accurateplacement, even if sensory responses are available. As discussed above,EMG is a tool which records electrical activity of skeletal muscles.This sensing feature provides an objective criterion for the clinicianto determine if the sacral nerve stimulation results in adequate motorresponse rather than relying solely on subjective sensory criteria. EMGcan be used not only to verify optimal lead position during leadplacement, but also to provide a standardized and more accurate approachto determine electrode thresholds, which in turn provides quantitativeinformation supporting electrode selection for programming. Using EMG toverify activation of motor responses can further improve the leadplacement performance of less experienced operators and allow suchphysicians to perform lead placement with confidence and greateraccuracy.

In one aspect, the system is configured to have EMG sensing capabilityduring re-programming, which can be particularly valuable. Stimulationlevels during re-programming are typically low to avoid patientdiscomfort which often results in difficult generation of motorresponses. Involuntary muscle movement while the patient is awake mayalso cause noise that is difficult for the physician to differentiate.In contrast to conventional approaches, EMG allows the clinician todetect motor responses at very low stimulation levels (e.g.,sub-threshold), and help them distinguish a motor response originated bysacral nerve stimulation from involuntary muscle movement.

Referring to FIG. 6, several cable sets are connected to the clinicianprogrammer. The stimulation cable set consists of one stimulationmini-clip 3 and one ground patch 5. It is used with a foramen needle 1to locate the sacral nerve and verify the integrity of the nerve viatest stimulation. Another stimulation cable set with four stimulationchannels 2 is used to verify the lead position with a tined stimulationlead 20 during the staged trial. Both cable sets are sterilizable asthey will be in the sterile field. A total of five over-the-shelfsensing electrode patches 4 (e.g., two sensing electrode pairs for eachsensing spot and one common ground patch) are provided for EMG sensingat two different muscle groups (e.g., perineal musculature and big toe)simultaneously during the lead placement procedure. This provides theclinician with a convenient all-in-one setup via the EMG integratedclinician programmer. Typically, only one electrode set (e.g., twosensing electrodes and one ground patch) is needed for detecting an EMGsignal on the big toe during an initial electrode configuration and/orre-programming session. Typically, these over-the-shelf EMG electrodesare also provided sterile though not all cables are required to beconnected to the sterile field. The clinician programmer 60 allows theclinician to read the impedance of each electrode contact whenever thelead is connected to an EPG, an IPG or a clinician programmer to ensurereliable connection is made and the lead is intact. The clinicianprogrammer 60 is also able to save and display previous (e.g., up to thelast four) programs that were used by a patient to help facilitatere-programming. In some embodiments, the clinician programmer 60 furtherincludes a USB port for saving reports to a USB drive and a chargingport. The clinician programmer may also include physical on/off buttonsto turn the clinician programmer on and off and/or to turn stimulationon and off.

III. Charging of Fully Implanted Neurostimulation Systems

In one aspect, a neurostimulation system in accordance with the presentinvention is fully implantable and powered with a rechargeable batterythat allows the system to provide therapy over the lifetime of thedevice with only periodic transcutaneous charging by an external CD.This feature increases the useful life of the neurostimulation system ascompared to conventional neurostimulation systems that utilize anon-rechargeable batteries which must be surgically removed and replacedevery three to four years. This conventional approach to fully implantedneurostimulation systems clearly results in significant discomfort andinconvenience for the patient. In addition, many patients may bereluctant to receive a therapy that requires periodic surgicalintervention every few years. In contrast, a neurostimulation systemutilizing transcutaneous charging in accordance with the principlesdescribed herein allows such a system to function for 10 years or morewithout invasive interventions to replace a battery, thereby improvingpatient comfort and acceptance of implanted neurostimulation therapies.

In one aspect, the systems and methods provide transcutaneous chargingof implanted devices by wireless charging that uses an electromagneticfield to transfer energy between two objects. This approach uses acharging station or device that sends energy through a magnetic orinductive coupling to an energy receiving unit of the implanted device,which then uses that energy to charge a battery in the implanted device.Such charging methods typically use an external device with a chargingcoil that creates an alternating electromagnetic field from within thecharging unit, and a second coil in the implanted device in which anelectromagnetic field is induced, which the implanted device thenconverts back into electrical current to charge the battery. The coilsmust generally be in close proximity to form an electrical transformerand maintained in close proximity for a duration of time sufficient tofully charge the battery. In many conventional devices, the coilconfigurations are such that the coils must be placed in closeproximity, typically less than a few centimeters. While wirelesscharging at greater distances can be achieved through various otherapproaches, such as resonant inductive coupling, these approaches mayrequire precise alignment between coils, while other approaches mayrequire coils of increased size and/or high powered charging. Wirelesscharging can be further understood by reference to U.S. Pat. No.6,972,543, entitled “Series resonant inductive charging circuit,” whichis incorporated herein by reference for all purposes.

The above noted aspects of wireless charging present substantialchallenges to charging of implanted medical devices, since it isdesirable for such devices to be of reduced size and weight, as well asto minimize exposure of the patient to high-powered charging stations.These aspects of wireless charging are particularly challenging in termsof implanted neurostimulation devices, which are typically implanted ata greater depths, such as a depth of about 3 cm, beneath a thin layer ofmuscle and/or fatty tissues in a lower back of the patient, where thepatient cannot readily access or observe the placement and/or alignmentof an external charging device. Given these challenges associated withwireless charging of implanted neurostimulation devices, conventionalneurostimulation devices have utilized non-rechargeable batteries withlife-times of about three to four years. While this approach avoids theabove noted drawbacks, it is also subjects the patients to periodicinvasive surgical procedures every time the battery needs to bereplaced.

In one aspect, the system and charging methods of the present inventionovercome these challenges associated with wireless charging due in partto the unique construction of the wireless receiving unit of theneurostimulation device and external CD, and also by use of certainfeatures that improve positioning and alignment of the external CD withthe implanted device to allow for more robust, consistent charging ofthe implanted device. In addition, the features described herein allow apatient to achieve that precise positioning and alignment with relativeease, without the aid of a caretaker or medical personnel. Furthermore,the above objectives are provided while still allowing for an implantedneurostimulation device of reduced size and weight and while maintainingpatient mobility by use of a portable external charging device thatremains attached to the patient during charging.

In one aspect, the systems and methods described herein allow fortranscutaneous charging of a fully implanted neurostimulation device bya portable external charging device adhered to the patient with anaffixation device for a duration of time, typically less than a fewhours, such as within two hours or less. In one aspect, the attachmentdevice is adapted to allow placement of the external CD by the patientin a position and/or alignment suitable for wireless charging and tomaintain that position and/or alignment for the duration of charging.Examples of such attachment devices are shown in FIGS. 7A-7C anddescribed further below.

A. Implant Battery Charging Protocol

In some embodiments, the IPG of the neurostimulation system includes acharging coil adapted to capture energy necessary to recharge theinternal battery. The battery voltage is measured through an Analog toDigital (A/D) converter of the IPG and is also monitored by the batterymonitor during charging. The battery monitor compares the batteryvoltage with a voltage reference. Based on the battery monitor outputs,the current charger inside the implant is controlled accordingly. Whenthe battery voltage is above 3.0V, it is in the normal charging mode.The charging current is set to the default value of ˜25 mA (C/2).Charging will stop when the battery voltage reaches 4.05V to preventover-charge. To charge up a battery with battery voltage between 2.5Vand 3.0V, a smaller charging current (˜2.5V) will be used until itreaches 3.0V where the battery goes into the normal charging mode. Insome embodiments, the IPG charging circuitry is designed in a such waythat no recharging is possible when the battery voltage is below 2.5V,to avoid potential thermal runaway causing rapid temperature increase ofthe battery, which is unlikely though due to the low capacity of theover-discharged battery. Field testing has demonstrated that such abattery can be safely recharged from a very low voltage state (0.1V).The battery voltage dropping below 2.5V is a very rare occurrence,because the IPG will be forced into a hibernation mode when the batteryvoltage drops below 3.0V during which the battery could only be drainedby a tiny leakage current such that it would take more than one year forthe battery voltage to drop below 2.5V from 3.0V. In some embodiments,the capacity of the implant battery is 50 mAh such that at nominalstimulation settings for OAB, the IPG lasts approximately two weeksbefore needing recharge.

In some embodiments, the external CD is a mobile puck-shaped device thatis configured to provide wireless and transcutaneous recharging of theimplanted IPG while maintained at a suitable position and/or alignmenton the patient. The CD includes a microcontroller which handles controlof charging and communication with the IPG. The CD also includes abattery, which can be recharged in a charging station or by couplingdirectly to a power source, which allows for charging while the patientis mobile. The CD is shaped and dimensioned to fit comfortably in a handof the patient to facilitate placement of the CD on the patient forrecharging, as well as to allow ready handling of the CD by the patient.In some embodiments, the CD includes a temperature sensor to ensure thatthe charger will never overheat. The charger monitors the batterycharging status and automatically shuts itself off when the implantbattery is fully charged.

In one aspect, the CD is a portable device having an enlarged upperportion and a protruding circular portion on a underside thereof. Theenlarged upper portion, which typically includes the rechargeablebattery and associated electronics and microcontroller, is dimensionedso as to be easily held by a user to facilitate handling and positioningof the CD by the patient. The protruding circular portion that housesthe charging coil and includes a substantially planar surface forengaging the skin of the patient over the implanted IPG. While the CD isdepicted as a puck-shaped device it is appreciated that the CD can bedefined in various other shapes while still providing certain featuresof the various aspects described herein.

FIG. 6A shows an example of an external, portable CD 50 in accordancewith the aspect described above. The CD includes a puck-shaped upperportion that contains a rechargeable battery that can support at least 2hours of continuous charging. This portion also includes an on/offbutton with an indicator light 52 indicates the charger battery status.Various differing colors or blinking can be used to indicate differingstates. For example, a green light indicates that the charger battery isat a good charging state and should provide a full charge for a depletedIPG battery (e.g. up to 2 hours of charging); an amber light indicatesthat the charger battery has energy to provide limited amount ofcharging but may not be enough to fully charge a depleted IPG battery. Aflashing amber light indicates that the CD has insufficient charge foreven a partial charge to the IPG. The indicator is flashing green whilethe CD is being charged. The indicator illuminates only while the CD ison; the indicator is OFF when the CD is OFF. The circular portion 53 atbottom protrudes outwards so that the charging coil can be in closerproximity to the IPG to facilitate charging at greater depth, forexample depths greater than 2 cm, typically up to depths of about 3 cm.

The CD may be charged by multiple options, such as those in FIG. 6B,which show a designated charging station 55, USB power cables 57, andmay utilize USB power adapters 58 to for use with a wall outlet or apower outlet in a car.

FIG. 6C shows another example CD 50 that includes a puck-shaped upperportion having an indicator light 52 and a protruding circular bottomportion (not shown). The upper portion, in this embodiment, includes aflattened side, which can facilitate handling by the patient androtational orientation, as described further below. FIG. 6D shows acharging station 55 that utilizes a circular depression for receivingthe protruding circular bottom portion of CD 50 to facilitate chargingthrough the charging coil housed therein.

In some embodiments, to get the recharging started, the patient needs tomove the CD over the implanted IPG. The CD provides audio feedback toassist the patient in finding the IPG. An audio transducer audiblyindicates when the IPG is near the charging coil to the IPG. The CDemits three short beeps when the CD is close to the IPG (enough to bedetectable) yet not within the charging zone, and a long beep toindicate the CD is in the IPG charging zone.

Optionally, a patient will then rotate the CD to achieve better angularalignment. A haptic feedback is provided when optimal angular alignmentis achieved between the CD and IPG. An audio tone signals that the IPGis now being charged by the CD. In addition, a periodic green flashinglight on the CD indicates the charging is currently on-going. If optimalalignment is not achieved within 15 seconds, but the charging field isstrong enough to charge the implant battery, the charging process willcontinue, and the audio will turn off. If the charger moves duringcharging and charging field is lost completely, the CD will emit 3 shortbeeps while in range yet not in the IPG charging zone. This alerts theuser that the CD is off target and needs to be re-located over the IPG.When charging is complete, the CD provides a user indication thatcharging is complete and powers off. For example, the CD can output aunique series of audio tones (e.g. three short beeps) that indicate theend of charging and the flashing green light will be off. In someembodiments, a watchdog timer is used to verify that the microcontrolleris operational. In the event of program malfunction, the microcontrollerwill enter a safe state that either powers down the coil or turns offthe coil drive.

By utilizing the devices and charging methods described herein, the IPGcan be recharged at greater depths, such as about 3 cm. Having a deepcharging depth allows for improved patient comfort during charging as itallows the implant to be placed in a desirable location within tissueswhile still allowing for transcutaneous wireless charging with aportable CD. To efficiently recharge the described, however, a preciseposition and/or alignment of the CD must be achieved and reasonablymaintained for a duration of time sufficient to complete charging of theIPG battery. This can be accomplished by use of various affixationmethods and devices adapted for use with the CD, such as those shown anddescribed below.

B. Example Affixation Devices

In one aspect, the carrier device includes a frame releasably coupleablewith the CD and having multiple outwardly extending tabs with a pressuresensitive adhesive suitable for adhesively securing the CD to the skinof the patient. The frame is configured to allow the CD to contact askin of the patient directly over the implanted IPG so as to minimizedistance between the CD and implanted IPG.

FIG. 7A shows such a carrier device adapted for use with a CD 50 devicein accordance with embodiments of the invention. In this example, the CD50 has a puck-shaped outer housing 51 that is circular in shape thatinclude a circular protruding portion 53 in which the charging coil isat least partly disposed. The carrier 1 is defined by a frame 2 having acircular opening 3 through which the circular portion 53 can be insertedand mounted into the carrier 1. The carrier 1 includes multiple tabs 5,for example three tabs, disposed circumferentially about the frame 2 andextending laterally outward from the opening in which the CD 50 ismounted. Each tab includes an adhesive surface 6 having an adhesive foradhering the carrier to the skin of the patient upon contact. Theadhesive is a biocompatible pressure-sensitive adhesive havingsufficient adhesive strength to affix the carrier to the patient's skinand support the CD 50 mounted in the carrier 1 for at least a durationof time required to fully charge the device, Durations of charging maybe within a range of about 30 minutes to five hours, typically about 2hours or less.

In another aspect, the carrier 1 includes a mounting interface 4 bywhich the CD 50 is releasably coupled with the carrier 1. In someembodiments, the mounting interface 4 engages a corresponding mountingfeature 54 of the CD 50 so as to securely couple the CD 50 within thecarrier 1 while still allowing rotation of the CD 50 relative thecharging device. In this example, the mounting interface 4 is a lip orridge and the corresponding mounting feature 54 is a groove extendingabout the circular protruding portion 53. The CD 50 is releasablycoupled with the carrier 1 in preparation for charging by inserting thecircular protruding portion 53 through the mounting hole 3 until the lip4 is fittingly received within a corresponding groove 54. It isappreciated that since carrier couples with CD along the mountinginterface disposed about the circular protruding portion that such acarrier could be used with a CD having an upper housing designed invarious other shapes, for example the CD in FIG. 6C or a CD having anupper housing that is non-circular in shape.

FIG. 7B shows an alternative carrier or attachment device comprising aband 9 adapted for use in affixing the CD at a desired position and/oralignment on the patient for charging. Such a band can be configuredaccording to various differing dimensions depending on where the desiredaffixation location is on the patient's body. For example, for chargingof an IPG implanted in a lower back of the patient, the band may bedimensioned as a band having dimensions similar to a belt so as toextend, at least partly, about a patient's waist while supporting the CDat the proper location and/or alignment at the lower back. For otherneurostimulation therapies where the IPG is implanted in various otherlocations, for example an upper arm or chest, the band 9 may bedimensioned as an upper arm band or as a holster to extend across thechest.

FIG. 7C shows yet another alternative carrier comprising an adjustablebelt 9′ having coupling features 9 a and 9 b at opposing ends that allowa patient to adjust the belt as desired, typically to fit about theirmid-section. Belt 9′ can be formed of a breathable and stretchablefabric so as to increase comfort to the patient during charging.Coupling features 9 a, 9 b can be interfacing features (e.g. snaps, hookand loop, Velcro®), or any suitable coupling means. Belt 9′ furtherincludes an circular aperture 3 through which the protruding circularportion 53 of CD 50 can be inserted so that, when the belt is worn, CD50 can be maintained in a lower back region for charging of an implantedIPG for the duration of charging. This location is particularlyapplicable to a sacral neuromodulation system as described herein,although it is appreciated that such a belt could be used on a chest orin various other locations as needed for various other types oftreatment systems. Belt 9′ can include a semi-rigid or rigid frame 2disposed about circular aperture 3 that includes a mounting interface 4that releasably couples with a corresponding interface of CD 50 (e.g.snap-fit or tongue-in-groove interface). In this embodiment, mountinginterface 4 is axisymmetric about a normal axis through a center of thecircular aperture such that CD 50 can be rotated, preferably by 180degrees or more, to allow rotation of CD 50 while coupled within belt9′. As in other embodiments described herein, mounting interface can beconfigured with sufficient resistance to maintain a position of CD heldwithin, once CD is rotated into a desired position.

FIGS. 8A-8B shows a patient mounting an example CD 50 within carrier 1,similar to that shown in FIG. 7A. The patient positions carrier 1 withthe adhesive surface of the tabs 5 facing away from the CD 50 theninserts the protruding circular bottom portion 53 of CD 50 through thecircular aperture 3 of carrier 1. With two hands, the user can thenpress against both the upper puck-shaped housing of CD 50 and thecarrier frame 2 until the mounting interface 4 snaps into thecorresponding interface 54 of CD 50. The patient can then press on tabs50 to move frame 2 into the inverted configuration, if not alreadywithin the inverted configuration. A liner disposed over each of theadhesive portions of tabs 5 can then be removed and the planar engagingsurface of the circular protruding portion 53 of CD 50 can then beapplied to the body and positioned, as described further below.

FIGS. 8C-8D shows a cross-section of an adhesive carrier device, similarto that of FIG. 7A, having a frame 2 with a mounting hole 3 extendingtherethrough and multiple tabs 5 extending laterally outward from theframe 2. The tabs are movable between a first position, shown in FIG.8C, and a second position, shown in FIG. 8D. As shown in FIG. 8C, thetabs in the first position extend upwards away from the plane P alongwhich the frame 2 of the carrier extends. The tabs in the first positionare angled upwards by angle a, which is typically 90 degrees or less,preferably about 45 degrees or less, even more preferably about 30. Thisupwards angling provides clearance for the CD 50 mounted in the carrierthrough hole 3 while maintaining the adhesive surface 6 spaced away fromthe patient's skin when the CD mounted within the carrier 1 is placed onthe patient's skin during initial positioning of the CD. FIG. 8D showsthe carrier 1 with the tabs 5 in the second position extending towardsan opposite direction relative the plane P so as to engage a skin of thepatient with the adhesive portions 6. The tabs in the first position areangled downwards by angle a′, which is less than 45 degrees, preferablyabout 30 degrees or less, so as to engage the patient's skin whilemaintaining the CD mounted therein against the patient's skin.

In one aspect, the carrier includes one or more tabs are formed of amaterial sufficiently stiff to maintain the first position and thesecond position when static, yet sufficiently flexible to bend slightlyso as to conform to the skin of the patient when in the second positionso as to maintain the CD 50 mounted in the carrier 1 against thepatient's skin for the duration of charging.

In one aspect, the carrier includes a spring-type mechanism or featurethat facilitate ready deployment of the multiple adhesive tabs intoengagement with a skin of the patient when the charger device is in asuitable position for charging, as may be indicated by an audible and/orhaptic signal from the charging device. Such a configuration isadvantageous in a sacral neuromodulation system in which the IPG isimplanted in a lower back region and the patient is positioning thecharging device in the lower back region with a single hand. Inresponse, to an audible and/or haptic signal output from the chargingdevice that indicates a suitable position for charging, the patient caneffect deployment of multiple adhesive tabs by the spring-type mechanismor feature of the charging device carrier. This action can be effectedby a pressing against the carrier with a finger of the single hand, forexample by depressing a button or lever of the carrier or by pressingagainst a single tab. In some embodiments, the spring-type feature isprovided by the design of the carrier frame itself. The carrier framecan comprise a semi-rigid or rigid material having a standardconfiguration and an inverted configuration, the frame resilientlyspringing toward the standard configuration from the invertedconfiguration.

In one such embodiment, the carrier 1 comprises a frame configured witha standard configuration, in which the tabs 5 are in the secondposition, and an inverted configuration, in which the tabs 5 are in thefirst position. Applying a slight force to one or more tabs in the firstposition in a direction of the arrow shown in FIG. 8C, causes the tabs 5to rapidly move or spring from the first position to the secondposition. In some embodiments, the tabs are interconnected through theframe such that application of this force to one tab causes the carrierto move from the inverted configuration to the standard configurationmuch in the same way that an inverted contact lens springs from aninverted state to its standard shape. In some embodiments, the tab maybe continuous about the frame and sufficiently flexible to move betweenthe standard configuration and an inverted configuration. Such aconfiguration is advantageous as it allows a patient to place the CD 50mounted in the carrier 1 and position the CD 50 over the implanteddevice 10 with a single hand and by application of the slight force tothe tab with a finger of the same hand, effect rapid movement of thetabs from the first position to the second position, thereby engagingthe adhesive surfaces 6 with the patient skin and affixing the carrierand CD at the desired location. The patient can then align the CD 50with the implanted device 10 by rotating the CD 50 mounted in thecarrier 1 affixed to the patient's skin with the same hand.

FIGS. 9A-9K illustrate a method of charging using a CD mounted in acarrier 1, in accordance with embodiments of the invention describedherein. FIG. 9A depicts the CD 50 resting in its charging station 55with the visual status indicator 52 showing that the device is chargedand ready to charge an implanted device (e.g. green light). Upon removalof the CD 50 from the charging station 55, as shown in FIG. 9B, the CDautomatically turns on. The user than releasably couples or mounts theCD 50 within an adhesive carrier device 1 by inserting the CD through aframe 2 of the carrier 1 such that the circular portion of CD extendsthrough the frame 2 while the movable tabs 5 are disposed in the firstposition, as shown in FIG. 9C. With the CD 50 properly mounted withinthe carrier 1, the patient removes any film present over the adhesiveportions 6 of the tabs and brings the CD 50 towards the implanted device10, as shown in FIG. 9D. The patient then places the portion of the CDprotruding through the carrier 1 in contact with the patient's skin S inthe general vicinity of the implanted device 10, as shown in FIG. 9E. Insome embodiments, the CD detects the presence of the nearby IPG 10 andmay output a user feedback, such as a visual, audio or haptic indicator,that the IPG 10 is in range but off target.

As shown in FIG. 9E, the patient then positions the CD 50 over the IPG10 by moving the CD along the skin S while the tabs 5 of the carrier arein the first position such that the adhesive portions 6 are spaced awayfrom the patient's skin to avoid affixation to the patient until the CDis properly positioned. Once the CD is properly positioned over the IPG10, as shown in FIG. 9F, the CD may output user feedback that indicatesthe CD is at the optimum position for charging. The user feedback willtypically be an audio or haptic alert since the patient may not be ableto see the visual indicator when the CD is being adhered to a patient'slower back. When properly placed, the distance d between the chargingcoil in the CD 50 is minimized. In many applications, such as a sacralneuromodulation treatment, the IPG 10 is implanted at a depth of about 3cm such that the distance d between the charging coil and IPG 10 isabout 3 cm when the CD 50 is maintained against the skin with theadhesive carrier.

FIG. 10 shows an overhead view of several different alignment of CD 50over an implanted IPG 10, shown in dashed lines. In this embodiment, theposition of optimal charging is the CD 50 directly over the IPG 10 in aparticular rotational alignment. Examples of unsuitable positions, whichcan be indicated by audible/haptic signals or lack of user feedbacksignals, are shown at right. It is appreciated that, in someembodiments, even if the IPG 10 is not quite in the optimal alignment,CD 50 can still signal that proximity is sufficient for charging,although less than optimal alignments can require longer chargingperiods.

FIGS. 11A-11C illustrate steps taken once the lateral positioning of theCD 50 is performed, as described in FIGS. 9D-9F. Once properlypositioned, the patient affixes the CD 50 to their skin by moving thetabs 5 of the carrier 1 from the first position to the second positionso that the adhesive surfaces engage the skin of the patient. This istypically done while the patient holds the CD against the skin with thepalm of their hand by flipping an upper edge of a tab downwards in thedirection of the arrows shown in FIG. 11A, which moves the tabs to asecond position that engages the skin of the patient, thereby affixingthe CD to the patient's skin S at the proper charging position over theIPG 10, as shown in FIG. 11B. The patient can then remove the support oftheir hand and the adhesive surfaces hold the CD in place.

Once the CD is properly positioned and affixed to the skin of thepatient, the patient can then adjust the rotational alignment of the CD.In one aspect, the carrier is configured such that the CD can bemanually rotated while mounted within, yet sufficiently secured suchthat the CD does not rotate when the CD is static, that is, when nomoment forced are applied to the CD. This may be accomplished byproviding a mounting interface that allows rotation but provides enoughfriction to prevent undesired rotation when the device is not beingmanually rotated by the patient. As shown in FIG. 11B, the patientrotates the CD 50 within the carrier until the CD is properly aligned,as detected by the CD and communicated to the patient through userfeedback. Typically, this user feedback is a second haptic and/or audioalert. This alert may be different or the same as the first alert. Thepatient then allows the CD to remain in place for a duration of timesufficient to allow charging of the device, which is typically at leastan hour, such as about two hours. In some embodiments the CD isconfigured to provide user feedback, such as a third alert, tocommunicate to the patient that charging is complete and the CD can beremoved and the carrier disposed of FIG. 12 shows an overhead view ofrotational adjustment of CD 50 while tabs 5 of carrier remain securelyadhered to a patient's skin S.

FIG. 13 illustrates a method of charging using an adhesive carrier inaccordance with embodiments of the invention. The method includes stepsof: releasably coupling a CD configured for transcutaneous charging ofan implanted powered medical device with a carrier having one or moretabs with an adhesive for adhering to a patient's skin 130; engaging thepatient's skin with the charging device coupled with the carrier whilethe one or more tabs are in a first position spaced away from thepatient's skin and positioning the charging device until at leastpartially positioned over or proximate the implanted medical 131; movingthe one or more tabs from the first position to a second position sothat the adhesive surface adheres to the skin of the patientsufficiently to support the CD coupled with the carrier for a durationof time sufficient to charge the implanted device 132; optionally,rotating the charging device while mounted in the carrier adhered to thepatient's skin until the charging device is in a pre-determinedalignment with the implanted device for charging 133; and charging theimplanted device by allowing the charging device to remain in closeproximity to the implanted device supported by the carrier adhered tothe patient's skin for the duration of time 134. In some embodiments,the CD may be configured to provide charging regardless of therotational alignment or may be configured to adjust the rotationalalignment of the charging coil as needed such that manual alignment bythe patient may not be required.

FIGS. 14A-14C illustrate schematics that represent differing chargingdevice configurations that provide indicator or alerts to the patient tofacilitate charging of the implanted medical device by the chargingdevice. Each configuration outputs to the patient differing indicators,typically audio and/or haptic alerts) that communicate various aspectsof the charging method to the patient. Typically, the configurationincludes unique indicators that indicate any or all of: a proximity ofthe charging device to the implanted device, an alignment of thecharging device relative the charging device that is suitable forcharging, an interruption in charging, and completion of charging.

FIG. 14A illustrates a configuration that includes a first indicator,such as three audible beeps, to indicate proximity of the chargingdevice relative the IPG; a second indicator, such as a long or sustainedtone, to indicated that the charging device is directly over the IPG; athird alert, such as a haptic vibration, to indicate suitable rotationalalignment of the charging device relative the IPG; and a fourth alert,such as rising audible tones, to indicate that charging has begun. Afifth alert, such as a buzzing tone, can be used to indicate thatcharging has been interrupted. In any of the embodiments described,after interruption is indicated, any of the preceding indicatorsdescribed can be used as needed, for example, if the charging devicemust be re-positioned or re-aligned to resume charging. A sixth alert,such as falling tones, can be used to indicate that charging iscompleted. In any of the embodiments described herein, each of the abovealerts is provided by the portable charging device based, at least inpart, on measurements or determinations by the charging device.

FIGS. 14B-14C illustrate additions configurations having a morestreamlined use of indicators than that of the configuration in FIG.14A. The charger device configuration of FIG. 14B utilizes a firstindicator, such as a long tone, to indicate an alignment of the chargingdevice with the IPG that is suitable for charging; a second indicator,such as a periodic ping, to indicate that charging is taking place; athird indicator, such as a periodic vibration, to indicate that charginghas been interrupted; and a fourth indicator, such as rising tones, toindicate that charging has been completed. The charger deviceconfiguration of FIG. 14C utilizes a first indicator, such as a longtone, to indicate an alignment of the charging device with the IPG thatis suitable for charging; a second indicator, such as a combination ofperiodic vibration and audible tones (e.g. three beeps and vibrationrepeating every five seconds), to indicate that charging has beeninterrupted; and a third indicator, such as a series of audible tones(e.g. a repeating series of rising tones), to indicate that charging hasbeen completed. It is appreciated that the above described embodimentsare illustrative and that such configurations can utilize variousdiffering types of alerts or combinations thereof in order tocommunicate an aspect of the charging process or methods to a patient.

FIG. 15 illustrates a method of transcutaneously charging an implantedmedical device with a portable charging device facilitated by use of thevarious indicators, in accordance with various embodiments. In thisexample, such a method includes: determining proximity and/or alignmentbetween charging coils of charger device and implanted IPG 150;outputting, with charger device, a first indicator indicating proximityand/or suitable alignment for charging 151; charging implanted IPG withcharger device 152; optionally, outputting a second indicator indicatingcharging 153; if charging interrupted, outputting a third indicatorindicating that charging has been interrupted; and determining thatcharging has completed and outputting a fourth indicator indicatingcharging completion 155.

FIG. 16 illustrates a portable charging device 50 having a protrudingcircular portion 53 on which is disposed an indicator graphic 59 tovisually represent a target alignment of charge device 50 relative theIPG. Such an indicator graphic 59 can be used as a training tool and areminder to the patient to enable consistent, accurate alignment whencharging. In this embodiment, indicator graphic 59 graphicallyrepresents the size and shape of the IPG in the target orientation bydepicting an outline of the IPG. The graphic 59 is provided on a planarsurface of protruding circular portion 53 that engages with a skin ofthe patient. While in this embodiment, graphic 59 is shown as an outlineof the IPG on a skin engaging surface of the circular portion 53, it isappreciated that such a graphic indicator could be included on variousother surfaces (e.g. top or opposing surface) and can include variousother graphics (e.g. arrows, text) to represent a target alignment ofthe charging device on the patient.

In the foregoing specification, the invention is described withreference to specific embodiments thereof, but those skilled in the artwill recognize that the invention is not limited thereto. Variousfeatures and aspects of the above-described invention can be usedindividually or jointly. Further, the invention can be utilized in anynumber of environments and applications beyond those described hereinwithout departing from the broader spirit and scope of thespecification. The specification and drawings are, accordingly, to beregarded as illustrative rather than restrictive. It will be recognizedthat the terms “comprising,” “including,” and “having,” as used herein,are specifically intended to be read as open-ended terms of art.

What is claimed is:
 1. A rechargeable medical implant system comprising:an implantable medical device having a rechargeable power source forpowering the implantable medical device while implanted within a patientand a wireless power receiving unit coupled with the rechargeable powersource; a portable charging device having a wireless power transmittingunit configured to magnetically couple with the wireless power receivingunit of the implantable medical device so as to recharge therechargeable power source; and a carrier removably coupleable with thecharging device, the carrier having one or more adhesive surfacesdisposed on one or more movable tabs configured to adhere to a skinsurface of the patient, wherein the one or more adhesive surfaces arenot in contact with a surface of the charging device, and wherein theone or more adhesive surfaces include a biocompatible adhesive withsufficient adhesive strength such that the adhesive surface isconfigured to adhere to the skin surface of the patient and support thecarrier coupled with the charging device for at least a duration of timesufficient to recharge the implantable medical device, and wherein thecarrier comprises a frame to which the one or more movable tabs areattached, wherein the frame defines a mounting interface at which thecharging device is removably coupleable, the mounting interface beingconfigured to resiliently receive the charging device within a snap-fit;wherein, when the charging device is coupled to the carrier, at least aportion of the charging device is configured to directly contact theskin surface of the patient; and wherein each of the one or more movabletabs is resiliently invertible between a first position and a secondposition when the carrier is coupled with the charging device placedagainst the skin surface of the patient, wherein: in the first position,the one or more tabs are configured to be spaced away from the skinsurface of the patient to facilitate manual positioning of the chargingdevice along the skin surface of the patient, and in the secondposition, the one or more tabs are configured to be urged against theskin surface of the patient to facilitate secure attachment of thecarrier to the skin surface of the patient with the adhesive surface forthe duration of charging.
 2. The system of claim 1, wherein the wirelesspower transmitting unit of the charging device includes a charging coilconfigured for magnetically coupling with the wireless power receivingunit when the charging device at least partially engages the skinsurface of the patient and is positioned at least partially over theimplantable medical device, wherein the carrier is configured to securethe charging device substantially flat against the skin surface of thepatient.
 3. The system of claim 1, wherein the one or more tabs extendcircumferentially, at least partly, about the charging device when thecarrier is coupled with the charging device such that the chargingdevice is configured to be secured substantially flat against the skinsurface of the patient when the carrier is adhered to the skin surfaceof the patient.
 4. The system of claim 1, wherein the carrier comprisesa frame to which one or more tabs are attached, wherein the framedefines a mounting interface at which the charging device is removablycoupled.
 5. The system of claim 4, wherein the mounting interface of thecarrier is configured to allow manual rotation of the charging devicerelative to the carrier while releasably coupled with the carrier. 6.The system of claim 5, wherein the mounting interface is configured witha dimensional fit with insufficient friction to allow rotation of thecharging device when the charging device is subjected to a rotationalforce and sufficient friction to maintain angular fixation of thecharging device within the carrier when the charging device is static.7. The system of claim 5, wherein the charging device comprises acircular or puck-shaped housing supporting and/or encasing the wirelesspower transmitting unit and associated charging coil at least partiallywithin a protruding circular portion of the housing.
 8. The system ofclaim 7, wherein the frame of the carrier comprises a circular ring andthe mounting interface comprises a ridge along an inside edge of thecircular ring that interfaces with an outer edge of the protrudingportion of the charging device.
 9. The system of claim 4, wherein theframe and the one or more tabs are integrally formed of a polymericmaterial.
 10. The system of claim 1, wherein the one or more tabs of thecarrier comprises three or more tabs that deflect between the first andsecond positions.
 11. The system of claim 1, wherein the one or moremovable tabs comprise a first movable tab and a second movable tab, andwherein the one or more movable tabs are operatively coupled to eachother such that application of force on the first movable tab causes thefirst movable tab and the second movable tab to invert.
 12. The systemof claim 1, wherein the one or more movable tabs are coupled to a springmechanism that is configured to facilitate inversion of the one ormovable tabs from the first position to the second position or from thesecond position to the first position.
 13. A rechargeable medicalimplant system comprising: an implantable medical device having arechargeable power source for powering the implantable medical devicewhile implanted within a patient and a wireless power receiving unitcoupled with the rechargeable power source; a portable charging devicehaving a wireless power transmitting unit having a charging coilconfigured to magnetically couple with the wireless power receiving unitof the implantable medical device so as to recharge the rechargeablepower source, wherein the charging coil is disposed within a protrudingportion of the charging device that is configured for placement againsta skin of the patient during charging; and a carrier removablycoupleable with the charging device, wherein the carrier comprises: asemi-rigid or rigid frame configured for removably coupling with thecharging device, wherein the frame includes an opening through which theprotruding portion of the charging device extends when the chargingdevice is coupled with the frame; and one or more tabs attached to theframe and extending laterally outward from the opening of the frame,wherein the one or more tabs include an adhesive surface having abiocompatible adhesive with sufficient adhesive strength such that theadhesive surface is configured to adhere to the skin of the patient andsupport the carrier coupled with the charging device with the protrudingportion configured to directly contact the skin of the patient for aduration of time sufficient to recharge the implantable medical device,wherein each of the one or more tabs is resiliently invertible between afirst position and a second position when the carrier is coupled withthe charging device placed against the skin surface of the patient,wherein: in the first position, the one or more tabs are configured tobe spaced away from the skin surface of the patient to facilitate manualpositioning of the charging device along the skin surface of thepatient, and in the second position, the one or more tabs are configuredto be urged against the skin surface of the patient to facilitate secureattachment of the carrier to the skin surface of the patient with theadhesive surface for the duration of charging; wherein the frame definesa mounting interface at which the charging device is removablycoupleable, the mounting interface being configured to resilientlyreceive the protruding portion of the charging device within a snap-fit.14. The system of claim 13, wherein the frame of the carrier comprises acircular ring and the one or more tabs of the carrier comprises three ormore tabs that resiliently deflect between the first and secondpositions.
 15. The system of claim 13, wherein the opening is circularand the one or more tabs extend circumferentially, at least partly,about the opening such that the protruding portion of the chargingdevice is configured to be maintained substantially flat against theskin of the patient when the charging device is coupled to the carrierand the tabs are adhered to the skin of the patient.
 16. The system ofclaim 13, wherein the frame and the one or more tabs are integrallyformed of a polymeric material.
 17. The system of claim 13, wherein themounting interface is configured to allow manual rotation of thecharging device relative to the carrier while releasably coupledtherein.
 18. The system of claim 17, wherein the is configured to securethe charging device to the carrier while allowing manual rotation of thecharging device.
 19. The system of claim 17, wherein the mountinginterface of the carrier is configured to interface with a correspondingfeature of the charging device in a tongue-in-groove type constructionso as to secure the charging device to the carrier while allowing manualrotation of the charging device.
 20. The system of claim 17, whereinmounting interface is dimensioned to provide sufficient friction toinhibit rotation of the charging device coupled within the carrier whenthe charging device is static.
 21. The system of claim 13, wherein theone or more tabs comprise a first tab and a second tab, and wherein theone or more tabs are operatively coupled to each other such thatapplication of force on the first tab causes the first tab and thesecond tab to invert.
 22. The system of claim 13, wherein the one ormore tabs are coupled to a spring mechanism that is configured tofacilitate inversion of the one or tabs from the first position to thesecond position or from the second position to the first position.